I'm more interested in the day when there are so many drones, they spend more time fighting each other and forget about the humans all together. We may never even see them, dogfighting above the clouds, save for a the perpetual flutter of broken parts falling from the heavens.
Another possibility.. cities protected by phalanxes of model rocket sized guided missiles scanning perpetually for enemy drones.
That's nonsensical. The chances of drone armies being so perfectly matched they always fight to a stalemate are basically zero. Ultimately one side will win, and then it will have a free hand. It's no different than a conventional air war in that regard.
Another possibility.. cities protected by phalanxes of model rocket sized guided missiles scanning perpetually for enemy drones.